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macdudesir

macrumors 6502
Original poster
Jan 16, 2011
363
84
Blacksburg, VA
I have a 27" core i3 imac with the ATI 5670 Graphics card and for the life of me I cant get the fans to speed up! It actually annoys me because i feel like the iMac is not working as hard as possible. I have currently been running 5 yes > /dev/null"s in terminal for 30 min and the cpu fan is still at 939rpm and the cpu temp is staying at 60C. I even tried doing that while running World of Warcraft on ultra settings and still the fans did not speed up. I've read a lot of overheating iMac threads but never a non-overheaing iMac thread...So i want to hear from you guys if your iMac doesn't overheat. I just want to see how many good iMac's are out there.:D lkjsdfglkj.png
 
Last edited:

GGJstudios

macrumors Westmere
May 16, 2008
44,545
943
...I cant get the fans to speed up!
Your fans will only speed up when temps are sustained for a while at a high enough level to make it necessary. Your temps are no where near high enough to require faster fan speeds. Relax and let your Mac do its job. It will spin them up, as needed.
 

macdudesir

macrumors 6502
Original poster
Jan 16, 2011
363
84
Blacksburg, VA
Normal??

Your fans will only speed up when temps are sustained for a while at a high enough level to make it necessary. Your temps are no where near high enough to require faster fan speeds. Relax and let your Mac do its job. It will spin them up, as needed.

Thanks for your reply. I am confident that the fans will speed up if they need to. I'm just kind of annoyed that the temp wont go above 60C because again, I feel like it's not working hard enough. Or maybe the cooling is just that efficient without speeding up the fans? Also the temp rose quickly to 60C and stayed there for about 25 min.
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
582
Finland
27" iMac's cooling is designed for 95W CPUs while your CPU is 73W. That explains why the temps stay so low.
 

macdudesir

macrumors 6502
Original poster
Jan 16, 2011
363
84
Blacksburg, VA
Is OS X downclocking my CPU?

Also, i have windows 7 in bootcamp on my imac and the temperatures go up way faster and way higher and the fans do speed up. I've heard about Apple downclocking the graphics card in the older models but not this one and never heard of them downclocking the CPU. Or is it just the way OS X manages the CPU? In windows i easily get up to 73C on the processor and hear the fans speed up. Sorry for so many questions i am fairly new to mac. Thanks:)
 

alust2013

macrumors 601
Feb 6, 2010
4,779
2
On the fence
As for not getting too hot, it certainly is working hard enough, as you can see the processor is at full load in your screen shot. In Windows, it does generally get a bit hotter for whatever reason. My computer does that as well, so there's nothing to worry about, especially since your CPU can handle up to about 220F. OS X is certainly not downclocking your CPU.
 

macdudesir

macrumors 6502
Original poster
Jan 16, 2011
363
84
Blacksburg, VA
Yaay!

Ok just an update i got the CPU fan to speed up. It was 83 degrees where i live today so that heat got to it and i ran a CPU test app and the cpu went to 62C for 5 min and then the fans started ramping up slowly to 2101rpm :) Man this thing can move some air! So i guess the 63 degrees temperature where my imac was last time was too cool for it to get hot lol thanks again to all that responded :)
 

infidel69

macrumors regular
Feb 25, 2011
202
0
So you're dissapointed because your imac doesn't overheat? That's a good problem to have. You should be careful of what you wish for you might just get it.
 
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